Peroxy bridges

Addition of an organolithium and Grignard reagent across the peroxy bridge of endoperoxides gives c/s-cyclohex-2-en-l,4-diols. Alkyl, cycloalkyl, alkenyl and aryl moieties can be transferred to oxygen <96TL6635>. 

We have initiated a study of the photoreduction of a series of paramagnetic peroxy-bridged dicobalt ammines. All of these complexes, which are shown below, contain the (Co-O-O-Co)5 + group, which best present evidence indicates should be represented as (Co -O-O-Com)5+, although ESR studies indicate that the extra electron is to some extent delocalized over the cobalt centers.78,79,82 Our idea was derived from Sykes report in 196363 that solutions of l-p in sunlight in dilute acid were decomposed according to the stoichiometry shown in reaction (29). 

In one instance, however, clear evidence has been obtained to suggest the formation of a peroxynitrate intermediate. Thus, the nickel complex Ni(NO)CI(diphos) reacts with 02 either in dimethylformamide or on irradiation in dichloromethane to form the nitro complex Ni(N02)Cl(di-phos). Evidence for the formation of a d9 nickel(I) intermediate came from ESR studies. This intermediate was considered to be the peroxy-bridge species (4) and the reaction sequence was believed to follow the sequence shown in Scheme 1. 

These secondary ozonides are more stable than primary ozonides. Even if the peroxy bridge is shielded by steric demanding groups leading to isolable products, they should not be isolated from an unmodified ozonolysis, because still more explosive side products (tetroxanes) may have been formed ... 

Figure 3 170 chemical shifts of some 1,2,4-trioxolanes with nonequivalent oxygen atoms within the peroxy bridge. 

Mc2Cd reacts with H2O2 to give a complex that is proposed to be the peroxy-bridged derivative MeCdOOCdMe, but was not isolated (equation 17)... 

A siloxane bridge is ruptured to form a peroxy bridge spedes ... 

The antitumour pregnane oligosaccharide (34) periplocoside C contains a very unusual peroxy bridge linking the D-arabino-hept-ulose and canarose units. 

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